Walking across the stage at the University of California Berkeley commencement feels especially sweet for Austin Whitney, who was paralyzed in a car accident that severed his spinal cord just below the hip.

Four years ago, the Southern California teen with a 4.0 GPA who loved sports and theater was forced to adapt to life in a wheelchair after he got behind the wheel while drunk and crashed into a tree.

"If somebody told me four years ago that I'd be walking at this graduation, I would have never believed them in a million years," Whitney told ABC News.

But Whitney did just that. With mechanical braces strapped to his body and motorized joints directed by a computer brain, he triumphantly walked across the stage at commencement -- a moment that reflected more than just the achievement of a four-year college degree.

"Everything over the last four years and all the emotions of it are really going to be climaxed in those two seconds," he said before his big day.

Hospitalized for 41 days after his crash, the incoming college freshman didn't let his paralysis hinder his plans to attend school. Ten days after being released from the hospital, he was in the classroom at UC Santa Barbara, where he spent his freshman year before transferring to UC Berkeley.

A double major in history and political science, Whitney began working with Homayoon Kazerooni, a professor of mechanical engineering, and a team of graduate students to develop the wearable robotic skeleton that helped him achieve his dream of walking again.

"I stood up in that machine for the first time on my 22nd birthday and that was the first time standing up really in four years," Whitney said. "I trust the machine an amazing amount. I know that machine like it is my own legs."

In fact, the team says Austin was so integral in providing feedback in development that they named the device after him.

Exoskeletons have come a long way since Kazerooni first began developing the robotics in 2000, after receiving a grant from the Defense Advanced Research Projects Agency to build a device that would enable users to carry heavier loads for longer periods of time.

Powerful batteries and faster computer processers have allowed Kazerooni and other engineers around the world make strides in developing and continually improving how exoskeletons operate.

Kazerooni said the Austin exoskeleton is simple and user-friendly, allowing for unsupervised use in the home.

"What we sacrifice in capability, we gain in accessibility and affordability. Just getting people to be upright and take steps forward is already a huge advance in increasing independence," Kazerooni told UC Berkeley.

Exoskeletons currently run about $100,000. Kazerooni doesn't have a deal in place yet to distribute the version named for Austin, but estimated it should cost no more than a motorized wheelchair.

For Whitney, the benefit of being able to walk with his classmates is priceless.

"Walking with the exoskeleton ... like any other graduate without a spinal cord injury ... [it's] truly, I guess, my final incorporation into this graduating class," he said.